Field of Invention
The present invention relates to a cartridge for a medium The invention is furthermore related to a method of manufacturing, and in particular additionally of filling such a cartridge.
Background Information
In the industrial sector, in the construction industry, for example of buildings, and also in the dental sector, cartridges are frequently used to store flowable liquids, frequently pasty or viscous to highly viscous substances and to dispense them for the respective application as required. Examples for such substances are joint sealing compounds, compounds for chemical dowels or chemical anchors, adhesives, pastes or impression materials in the dental sector. These cartridges are usually produced from plastic and are manufactured in an injection molding process.
A distinction is made between single-component systems in which the material to be dispensed is only made of one component and two-component or multicomponent systems in which at least two different components are stored in separate chambers of the same cartridge or in separate cartridges, wherein the components are intimately mixed on dispensing by means of a dynamic or static mixing apparatus. Examples for this are two-component adhesives or chemical dowels which only harden after the mixing of the two components. Two-component systems are in particular also used in the industrial sector for paints which are often used to generate functional protective layers such as for corrosion protection.
It is frequently the case that the cartridges include one (or more) axially displaceable conveying pistons by whose movement the material is dispensed from the chamber or chambers. It is understood that the chambers have to have sufficiently thick walls for this purpose in order to be able to withstand the pressure arising on the dispensing. In addition, the cartridges have to have sufficiently substantial wall thicknesses to be sufficiently diffusion-resistant. This is in particular important with respect to the storage to prevent a diffusing in or a diffusing out of the chemical substances and thus a degradation of the cartridge content as effectively as possible. Since such plastic cartridges are as a rule only designed for a single use, a substantial amount of waste results both with regard to volume and to mass, which is in particular also disadvantageous under aspects of environmental protection.
A known alternative to the plastic cartridges is represented by hoses in which the respective materials are stored. These hoses are then placed into a special support apparatus or dispensing apparatus to dispense their contents for the respective application. Such hoses are admittedly in particular much more favorable than cartridges from a waste volume aspect, but they have other disadvantages. Much more complex filling apparatuses are required to fill and close the hoses. In addition, their storage is more problematic since hoses are not able to stand so that special measures or packaging have to be provided for the storage. Problems with the leak tightness of such hoses can also occur. In addition, the mass of the residual volume in the hose which cannot be dispensed is relatively high. Hoses furthermore have the disadvantage that they are very sensitive toward mechanical influences, in particular toward sharp edges or pointed corners.
In addition to the aspect of environmental protection, the topic of sustainability is also increasingly gaining importance. The use of renewable starting materials, the minimization of the use of raw materials and energy as well as a reduction of waste which is as high as possible are increasingly gaining importance both with regard to the cartridge per se and to the volume of residual mass remaining in the cartridge.
The unfilled cartridges are traditionally transported by the cartridge manufacturers to the manufacturers of the filling materials (media) who then take care of the filling of the empty cartridges. Even though the unfilled cartridges have a relatively low weight, the costs for the transport of the empty cartridges from the cartridge manufacturers to the media manufacturers are relatively high since the empty cartridges have a relatively large volume and thus high space requirements on transport. The storage costs for the empty cartridges both at the cartridge manufacturers' and at the media manufacturers' are furthermore also relatively high due to the space requirements. These costs make up a not insubstantial portion of the total manufacturing costs of the cartridges.